About Optics & Photonics TopicsOSA Publishing developed the Optics and Photonics Topics to help organize its diverse content more accurately by topic area. This topic browser contains over 2400 terms and is organized in a three-level hierarchy. Read more.

Topics can be refined further in the search results. The Topic facet will reveal the high-level topics associated with the articles returned in the search results.

Abstract

We report for the first time on the experimental response of a Surface Plasmon Resonance fiber optic sensor based on wavelength modulation for hydrogen sensing. This approach of measuring the hydrogen concentration makes the sensor insensitive to intensity fluctuations. The intrinsic fiber sensor developed provides remote sensing and enables the possibility of multi-points sensing. The sensor consists of a multilayer of 35 nm Au / 180 nm SiO2/ Pd deposited on a step- index multimode fiber core. The sensitivity and selectivity of the sensor are optimal at a Pd thickness of 3.75 nm. The sensor is sensitive to a hydrogen concentration ranging between 0.5 and 4% H2 in Ar, with a response time less than 15 s.

Figures (5)

(a) Schematic representation of the way the sensitive material is deposited on the fiber core, after removing the cladding. (b) The simulated transmitted intensity as a function of the wavelength for two different SiO2 thicknesses. The line and the dashed line represent respectively the metallic and the hydrogenated states.

(a) Schematic representation of the role of each layer. The multilayer stack is deposited on the core of an optical fiber. Each curve shows the reflectance of the corresponding layer as a function of the incident angle. In an optical fiber the light propagates only for high angles (depending on the fiber NA).(b) The transmitted spectrum at the output of the fiber for various thickness. (The coupling is maximal when the intensity drops at 0.5 since only the TM polarized light is coupled to Surface Plasmon).